Cardiac electrophysiology and the athlete: a primer for the sports clinician.

Intense exercise requires a significant increase in cardiac output in order to meet the needs of the skeletal muscles for oxygenated blood. In order to improve cardiac performance, the autonomic nervous system increases sympathetic tone primarily through release of norepinephrine from postganglionic receptors to stimulate the ß-adrenergic receptors of the nodal and muscle tissue of the heart. This event initiates a signaling cascade focused on increasing the amount of calcium available to the contractile myofilaments in the cardiac cell. Failure of the myocytes to counterbalance the increase in inward ion flow or adequately sequester cytosolic calcium during diastole leads to potentially catastrophic electrical instability. In this review, the relationship between the cellular events initiated by exercise and the induction of arrhythmias associated with the long QT, Brugada, and Wolff-Parkinson-White syndromes; catecholaminergic polymorphic ventricular tachycardia; and the heritable cardiomyopathies are explored.

Joint Trauma System Clinical Practice Guideline: Acute Coronary Syndrome (ACS). 14 May 2021.

Deployed medical providers at all roles of care must be prepared to recognize and manage acute coronary syndrome (ACS). Under optimal conditions, treatment is initiated with medical therapy and may be followed by prompt coronary angiography and revascularization. Emergent percutaneous coronary intervention (PCI) is not available in most deployed locations, however, and the time for such intervention is often dependent on long-range evacuation. This CPG provides guidance on best management for ACS patients in the deployed and resource-constrained environment.

Constrictive pericarditis: a cause of exertion-induced dyspnea in a soldier with a prior sternotomy.

Diagnosing the underlying etiology of dyspnea on exertion in adults can be challenging, often requiring the clinician to distinguish cardiac or pulmonary pathological conditions from metabolic, neurological, or hematological conditions or from chest wall abnormalities. We report such a case involving a 29-year-old, male, active duty Army soldier. With a history of a median sternotomy, symptoms of right- and left-side heart failure, and examination findings suggesting elevated right atrial pressure, pericardial disease was pursued. Echocardiography and cardiac catheterization revealed constrictive physiological features, namely, elevation and near-equalization of right- and left-side pressures and ventricular interdependence, whereas computed tomography illustrated pericardial thickening, ultimately leading to the diagnosis of constrictive pericarditis. The patient was treated with a complete pericardiectomy, leading to symptom resolution and improved exercise capacity. This case report of a rare condition offers a concise etiological and physiological overview of constrictive pericarditis and demonstrates an effective multimodal diagnostic approach. The scientific evidence provided may assist general practitioners in making decisions to differentiate this clinical condition from similar cardiac or cardiopulmonary conditions.

Surgery Averted Using a Novel, Minimally Invasive Approach to Treat Very Severe Radial Artery Spasm.

A 42-year-old male admitted with a non-ST elevation myocardial infarction was referred for invasive angiographic assessment. Based on preprocedural assessment, the right radial artery approach was selected. Despite possessing none of the consensus risk factors for radial artery spasm, in addition to receiving standard arterial spasm prophylaxis and conscious sedation, the patient suffered very severe radial artery spasm with initial catheter placement, resulting in entrapment of a 5 Fr pigtail catheter within the left ventricle. After exhausting traditional methods for resolution of radial artery spasm, surgical intervention appeared to be the only remaining option for removal of the entrapped catheter. Prior to committing to surgery, use of an axillary nerve block to hinder sympathetic vascular tone was suggested and attempted. This intervention resulted in atraumatic catheter removal. We present a case of very severe radial artery spasm refractory to customary interventions, alleviated with a novel, minimally invasive technique, which spared surgical intervention.

Jugular venous pulse: window into the right heart.

Although physicians began associating conspicuous neck veins with heart disease almost three centuries ago, the jugular venous pulse remains an often ignored component of the physical examination. Many physicians have not invested in the necessary understanding of the technique, and there is a misconception that its examination is difficult and of limited clinical value. When performed properly, evaluation of the jugular venous pulse can be extremely useful in distinguishing the cause of dyspnea and edema. The normal jugular venous pulse is reviewed, and pulse wave abnormalities are described, including ways in which they can provide clues to the diagnosis of certain disease states, ranging from pericardial disease to conduction disturbances. The jugular venous pulse provides a window into the right heart and an occasional glimpse of left heart hemodynamics. By peering through this window, clinicians can gain valuable information in the diagnostic evaluation of the cardiovascular patient.